Blog - Electric Cars

How to build your own charger?

For building an EV charger, you will need a control circuit that communicates with the onboard charger in the vehicle using a special signal, which also switches on the relay. We sell several types of control circuits:

1. with a fixed charging current of 16A
2. with an integrated single-phase 230V AC relay
3. without an integrated relay for single-phase
4. three-phase charging with any charging currents (user-adjustable) and then the same in the DIN rail version.

If you buy the type without an integrated relay/contactor, you still have to buy a suitable AC relay/contactor.

For single-phase charging a 2-pole contactor/relay is sufficient but for a three-phase, you need a 4-pole contactor/relay for 400/230V.
Each charging station should also be equipped with a special current protector that detects the DC component as well. However, it is not necessary for operation, it is only a safety feature.

You must connect the charger control circuit to the vehicle with a special cable which besides the power wires (L1, L2, L3, N and PEN) also contains the CP (control pilot) signal wire that controls the onboard 230/400V AC charger integrated into the vehicle. The cables are available in two versions, 16 and 32A. For 99% of cars, the 16A cable is sufficient, as it is cheaper, lighter and more compact. In a three-phase connection, it allows charging with 11 kW of power.

The Type2 connector must be fitted with a resistor inside to inform the vehicle of the cross-section of the charging cable. For the 16A cable, a 680 Ohm resistor must be fitted between the PP (proximity pilot) contacts and the PEN earth wire, and 220 Ohm for 32A. These two resistors are supplied with the charging connector. The resistor is directly in the vehicle charging gun, the PP pole does not need to be led from the vehicle to the charger control circuit.